Structural Assessment of Highway 'N' Power Substation under Earthquake Loads

摘要

In this study, the Highway N Substation was analyzed with a finite element model (FEM) for its vulnerability. The rigid bus and electric switch components were characterized with full scale shake table tests. Each component of the substation was carefully modeled with due considerations of mass density, stiffness and geometries. Based on the FEM, modal analysis was conducted to identify the natural frequencies of the structure along with their corresponding mass participation factors. In response spectrum and time history analyses, the dynamic responses of main components, such as rigid buses and switches, were evaluated. The magnitude and location of the maximum moments were identified. The shake table tests on three Turner Electrics TMX switches indicated that the first three natural frequencies of the switches are approximately 7.41 Hz, 15.2 Hz and 22.9 Hz, respectively. They are significantly higher than their corresponding frequencies of the entire substation system. The tested switches consistently fractured at the base of their metal shaft, a critical component of the switch open-and-close mechanism, due to stress concentration and local manufacture defect.